Physical Inspection metering and evaluation of HVAC systems efficiency in tertiary buildings

Abstract

Since twenty years European Union produces Directive to decrease energy consumption. The building sector is one of the most affected, since the buildings we live and work are responsible of about one third of global European energy consumption. Heating, Ventilation and air conditioning systems (HVAC systems) are often unknown by end-users. Also building owner and manager do not know deeply how the systems is composed. In the present work the writer found numerous specific diagnosis and intervention on HVAC system to dramatically decrease energy consumption. Incredible energy savings are possible by simply check and set up the right schedule and set up of HVAC system. Numerous European funded project demonstrated the effectiveness of such approach. Two European project results are described: Harmonac and iSERVcmb. Harmonac set up standards for HVAC systems inspections, the main findings are related to: general lack of information about system/components effectively installed in a building, HVAC inspections needing of a specific knowledge, not available in the market, lack of knowledge on control system by maintenance service companies, general over sizing of Heating power, Cooling power and water flow, scarce availability of logged data concerning energy consumption. BMS (Building Management System), if properly designed and installed could decrease inspection time and increase energy efficiency. Nevertheless, the inspections carried out in those years show that few BMS were able to log energy data. With a correctly installed BMS data of consumption the strategy and schedule of HVAC system should be understand, and also pointed the major energy savings opportunities. Buildings long term metering shown that HVAC inspection is fundamental to ensure efficiency of systems and, as a result, the best performance in terms of energy savings and comfort. BMS system should help in this issue, but they have to be originally designed for this purpose. Short term metering demonstrated that such approach could be a low cost solution to understand system behaviour and potential improvement. Building owner approach to system inspection shown clearly that there is a common under estimation of energy savings that could be reached by simply control strategy management. Since is necessary to demonstrate to building owner how much energy (and money) is possible to save with metering and operation control, the writer believe that the next step is to provide robust benchmark for the most common activities. With benchmark data will be easier to understand the potential of energy savings that is possible to achieve in buildings. That will convince building owner and/or financial bodies and ESCO to invest in big refurbishment of existent building stock, that are just operated "as usual.